1. Field of the Invention
The present invention relates to a cooling device, an image projection apparatus, and an electronic apparatus.
2. Description of the Related Art
As a method of cooling a heat source, as disclosed for example in Japanese Patent Application Laid-open No. 2001-210766 and Japanese Patent Application Laid-open No. 2000-269674, there is a known method of pressing a heat dissipation plate against the heat source to enlarge a heat dissipation area and blowing cooling air to an enlarged heat dissipation portion. Furthermore, as a method of enhancing cooling efficiency, for example, a method of molding a heat dissipation plate with a material having high thermal conductivity is implemented. By molding the heat dissipation plate with the material having high thermal conductivity, the heat transmitted from a contact portion with the heat source can be uniformly spread over the entire heat dissipation plate. This results in an increase in the heat dissipation area, which enables the heat source to be effectively cooled.
It is also effective to increase a contact area between cooling air and a heat dissipation plate, as disclosed for example in Japanese Patent Application Laid-open No. 2001-210766 and Japanese Patent Application Laid-open No. 2000-269674. The heat dissipation plate heated by receiving heat from a heat source is cooled in a contact portion with the cooling air. Therefore, by enlarging the contact area with the cooling air, cooling efficiency can be enhanced. As a method of enlarging the contact area, a method of attaching fins to the heat dissipation plate is already known. By attaching the fins to the heat dissipation plate with a fine pitch and blowing the cooling air to spaces between pitches, the contact area with the cooling air can be enlarged, thus enhancing the cooling efficiency.
Moreover, a forced air cooling system for cooling a heat dissipation plate using a fan is adopted as disclosed for example in Japanese Patent Application Laid-open No. 2001-210766 and Japanese Patent Application Laid-open No. 2000-269674. The cooling capacity depends on wind speed of air passing through pitches of fins. Therefore, to enhance the cooling capacity, the wind speed of the air passing through the pitches needs to be increased, and because of this, the forced air cooling can obtain higher cooling effect than that of natural air cooling. A method of using a fan is common as the forced air cooling. Particularly, a cooling structure can be said common, in which an outlet port of a sirocco fan with high static pressure is disposed so as to face rectangular fins and to blow air discharged from the sirocco fan directly to the fins.
However, the conventional cooling method has a problem that when cooling efficiency is to be structurally enhanced, the structure is upsized caused by increasing the surface area of the heat dissipation plate and caused by requiring a larger more powerful fan in order to improve the cooling efficiency. Therefore, in either case, the structure is increased in size and weight, and therefore there remains a problem that it is difficult to store such a structure in a compact and lightweight electric apparatus.
In view of the conventional problems, there is a need to provide a cooling device capable of efficiently cooling an object to be cooled while downsizing the cooling device.